Contract Name:
Sushiswap_ZapOut_General_V3
Contract Source Code:
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// Copyright (C) 2021 zapper
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// Visit <https://www.gnu.org/licenses/>for a copy of the GNU Affero General Public License
///@author Zapper
///@notice this contract implements one click removal of liquidity from Sushiswap pools, receiving ETH, ERC20 or both.
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "../_base/ZapOutBaseV3.sol";
interface IUniswapV2Factory {
function getPair(address tokenA, address tokenB)
external
view
returns (address pair);
}
interface IUniswapV2Router02 {
function WETH() external pure returns (address);
function removeLiquidity(
address tokenA,
address tokenB,
uint256 liquidity,
uint256 amountAMin,
uint256 amountBMin,
address to,
uint256 deadline
) external returns (uint256 amountA, uint256 amountB);
function removeLiquidityETH(
address token,
uint256 liquidity,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline
) external returns (uint256 amountToken, uint256 amountETH);
}
interface IUniswapV2Pair {
function token0() external pure returns (address);
function token1() external pure returns (address);
function balanceOf(address user) external view returns (uint256);
function totalSupply() external view returns (uint256);
function getReserves()
external
view
returns (
uint112 _reserve0,
uint112 _reserve1,
uint32 _blockTimestampLast
);
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
}
interface IWETH {
function withdraw(uint256 wad) external;
}
contract Sushiswap_ZapOut_General_V3 is ZapOutBaseV3 {
using SafeERC20 for IERC20;
uint256 private constant deadline =
0xf000000000000000000000000000000000000000000000000000000000000000;
IUniswapV2Router02 private constant sushiswapRouter =
IUniswapV2Router02(0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F);
IUniswapV2Factory private constant sushiswapFactory =
IUniswapV2Factory(0xC0AEe478e3658e2610c5F7A4A2E1777cE9e4f2Ac);
address private constant wethTokenAddress =
address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
constructor(uint256 _goodwill, uint256 _affiliateSplit)
ZapBaseV2(_goodwill, _affiliateSplit)
{
// 0x exchange
approvedTargets[0xDef1C0ded9bec7F1a1670819833240f027b25EfF] = true;
}
event zapOut(
address sender,
address pool,
address token,
uint256 tokensRec
);
/**
@notice Zap out in both tokens
@param fromPoolAddress Pool from which to remove liquidity
@param incomingLP Quantity of LP to remove from pool
@param affiliate Affiliate address
@return amountA Quantity of tokenA received after zapout
@return amountB Quantity of tokenB received after zapout
*/
function ZapOut2PairToken(
address fromPoolAddress,
uint256 incomingLP,
address affiliate
) public stopInEmergency returns (uint256 amountA, uint256 amountB) {
IUniswapV2Pair pair = IUniswapV2Pair(fromPoolAddress);
require(address(pair) != address(0), "Pool Cannot be Zero Address");
// get reserves
address token0 = pair.token0();
address token1 = pair.token1();
IERC20(fromPoolAddress).safeTransferFrom(
msg.sender,
address(this),
incomingLP
);
_approveToken(fromPoolAddress, address(sushiswapRouter), incomingLP);
if (token0 == wethTokenAddress || token1 == wethTokenAddress) {
address _token = token0 == wethTokenAddress ? token1 : token0;
(amountA, amountB) = sushiswapRouter.removeLiquidityETH(
_token,
incomingLP,
1,
1,
address(this),
deadline
);
// subtract goodwill
uint256 tokenGoodwill =
_subtractGoodwill(_token, amountA, affiliate, true);
uint256 ethGoodwill =
_subtractGoodwill(ETHAddress, amountB, affiliate, true);
// send tokens
IERC20(_token).safeTransfer(msg.sender, amountA - tokenGoodwill);
Address.sendValue(payable(msg.sender), amountB - ethGoodwill);
} else {
(amountA, amountB) = sushiswapRouter.removeLiquidity(
token0,
token1,
incomingLP,
1,
1,
address(this),
deadline
);
// subtract goodwill
uint256 tokenAGoodwill =
_subtractGoodwill(token0, amountA, affiliate, true);
uint256 tokenBGoodwill =
_subtractGoodwill(token1, amountB, affiliate, true);
// send tokens
IERC20(token0).safeTransfer(msg.sender, amountA - tokenAGoodwill);
IERC20(token1).safeTransfer(msg.sender, amountB - tokenBGoodwill);
}
emit zapOut(msg.sender, fromPoolAddress, token0, amountA);
emit zapOut(msg.sender, fromPoolAddress, token1, amountB);
}
/**
@notice Zap out in a single token
@param toTokenAddress Address of desired token
@param fromPoolAddress Pool from which to remove liquidity
@param incomingLP Quantity of LP to remove from pool
@param minTokensRec Minimum quantity of tokens to receive
@param swapTargets Execution targets for swaps
@param swapData DEX swap data
@param affiliate Affiliate address
@param shouldSellEntireBalance If True transfers entrire allowable amount from another contract
*/
function ZapOut(
address toTokenAddress,
address fromPoolAddress,
uint256 incomingLP,
uint256 minTokensRec,
address[] memory swapTargets,
bytes[] memory swapData,
address affiliate,
bool shouldSellEntireBalance
) public stopInEmergency returns (uint256 tokensRec) {
(uint256 amount0, uint256 amount1) =
_removeLiquidity(
fromPoolAddress,
incomingLP,
shouldSellEntireBalance
);
//swaps tokens to token
tokensRec = _swapTokens(
fromPoolAddress,
amount0,
amount1,
toTokenAddress,
swapTargets,
swapData
);
require(tokensRec >= minTokensRec, "High Slippage");
uint256 totalGoodwillPortion;
// transfer toTokens to sender
if (toTokenAddress == address(0)) {
totalGoodwillPortion = _subtractGoodwill(
ETHAddress,
tokensRec,
affiliate,
true
);
payable(msg.sender).transfer(tokensRec - totalGoodwillPortion);
} else {
totalGoodwillPortion = _subtractGoodwill(
toTokenAddress,
tokensRec,
affiliate,
true
);
IERC20(toTokenAddress).safeTransfer(
msg.sender,
tokensRec - totalGoodwillPortion
);
}
tokensRec = tokensRec - totalGoodwillPortion;
emit zapOut(msg.sender, fromPoolAddress, toTokenAddress, tokensRec);
return tokensRec;
}
/**
@notice Zap out in both tokens with permit
@param fromPoolAddress Pool from which to remove liquidity
@param incomingLP Quantity of LP to remove from pool
@param affiliate Affiliate address to share fees
@param permitData Encoded permit data, which contains owner, spender, value, deadline, r,s,v values
@return amountA Quantity of tokenA received
@return amountB Quantity of tokenB received
*/
function ZapOut2PairTokenWithPermit(
address fromPoolAddress,
uint256 incomingLP,
address affiliate,
bytes calldata permitData
) external stopInEmergency returns (uint256 amountA, uint256 amountB) {
// permit
_validatePool(fromPoolAddress);
(bool success, ) = fromPoolAddress.call(permitData);
require(success, "Could Not Permit");
(amountA, amountB) = ZapOut2PairToken(
fromPoolAddress,
incomingLP,
affiliate
);
}
/**
@notice Zap out in a single token with permit
@param toTokenAddress Address of desired token
@param fromPoolAddress Pool from which to remove liquidity
@param incomingLP Quantity of LP to remove from pool
@param minTokensRec Minimum quantity of tokens to receive
@param swapTargets Execution targets for swaps
@param swapData DEX swap data
@param affiliate Affiliate address
*/
function ZapOutWithPermit(
address toTokenAddress,
address fromPoolAddress,
uint256 incomingLP,
uint256 minTokensRec,
bytes memory permitData,
address[] memory swapTargets,
bytes[] memory swapData,
address affiliate
) public stopInEmergency returns (uint256) {
// permit
_validatePool(fromPoolAddress);
(bool success, ) = fromPoolAddress.call(permitData);
require(success, "Could Not Permit");
return (
ZapOut(
toTokenAddress,
fromPoolAddress,
incomingLP,
minTokensRec,
swapTargets,
swapData,
affiliate,
false
)
);
}
function _validatePool(address poolAddress) internal view {
IUniswapV2Pair pair = IUniswapV2Pair(poolAddress);
address token0 = pair.token0();
address token1 = pair.token1();
address retrievedAddress = sushiswapFactory.getPair(token0, token1);
require(retrievedAddress == poolAddress, "Invalid Pool Address");
}
function _removeLiquidity(
address fromPoolAddress,
uint256 incomingLP,
bool shouldSellEntireBalance
) internal returns (uint256 amount0, uint256 amount1) {
IUniswapV2Pair pair = IUniswapV2Pair(fromPoolAddress);
require(address(pair) != address(0), "Pool Cannot be Zero Address");
address token0 = pair.token0();
address token1 = pair.token1();
_pullTokens(fromPoolAddress, incomingLP, shouldSellEntireBalance);
_approveToken(fromPoolAddress, address(sushiswapRouter), incomingLP);
(amount0, amount1) = sushiswapRouter.removeLiquidity(
token0,
token1,
incomingLP,
1,
1,
address(this),
deadline
);
require(amount0 > 0 && amount1 > 0, "Removed Insufficient Liquidity");
}
function _swapTokens(
address fromPoolAddress,
uint256 amount0,
uint256 amount1,
address toToken,
address[] memory swapTargets,
bytes[] memory swapData
) internal returns (uint256 tokensBought) {
address token0 = IUniswapV2Pair(fromPoolAddress).token0();
address token1 = IUniswapV2Pair(fromPoolAddress).token1();
//swap token0 to toToken
if (token0 == toToken) {
tokensBought = tokensBought + amount0;
} else {
//swap token using 0x swap
tokensBought =
tokensBought +
_fillQuote(
token0,
toToken,
amount0,
swapTargets[0],
swapData[0]
);
}
//swap token1 to toToken
if (token1 == toToken) {
tokensBought = tokensBought + amount1;
} else {
//swap token using 0x swap
tokensBought =
tokensBought +
_fillQuote(
token1,
toToken,
amount1,
swapTargets[1],
swapData[1]
);
}
}
function _fillQuote(
address fromTokenAddress,
address toToken,
uint256 amount,
address swapTarget,
bytes memory swapData
) internal returns (uint256) {
if (fromTokenAddress == wethTokenAddress && toToken == address(0)) {
IWETH(wethTokenAddress).withdraw(amount);
return amount;
}
uint256 valueToSend;
if (fromTokenAddress == address(0)) {
valueToSend = amount;
} else {
_approveToken(fromTokenAddress, swapTarget, amount);
}
uint256 initialBalance = _getBalance(toToken);
require(approvedTargets[swapTarget], "Target not Authorized");
(bool success, ) = swapTarget.call{ value: valueToSend }(swapData);
require(success, "Error Swapping Tokens");
uint256 finalBalance = _getBalance(toToken) - initialBalance;
require(finalBalance > 0, "Swapped to Invalid Intermediate");
return finalBalance;
}
/**
@notice Utility function to determine quantity and addresses of tokens being removed
@param fromPoolAddress Pool from which to remove liquidity
@param liquidity Quantity of LP tokens to remove.
@return amountA Quantity of tokenA removed
@return amountB Quantity of tokenB removed
@return token0 Address of the underlying token to be removed
@return token1 Address of the underlying token to be removed
*/
function removeLiquidityReturn(address fromPoolAddress, uint256 liquidity)
external
view
returns (
uint256 amountA,
uint256 amountB,
address token0,
address token1
)
{
IUniswapV2Pair pair = IUniswapV2Pair(fromPoolAddress);
token0 = pair.token0();
token1 = pair.token1();
uint256 balance0 = IERC20(token0).balanceOf(fromPoolAddress);
uint256 balance1 = IERC20(token1).balanceOf(fromPoolAddress);
uint256 _totalSupply = pair.totalSupply();
amountA = (liquidity * balance0) / _totalSupply;
amountB = (liquidity * balance1) / _totalSupply;
}
}
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "../oz/0.8.0/access/Ownable.sol";
import "../oz/0.8.0/token/ERC20/utils/SafeERC20.sol";
abstract contract ZapBaseV2 is Ownable {
using SafeERC20 for IERC20;
bool public stopped = false;
// if true, goodwill is not deducted
mapping(address => bool) public feeWhitelist;
uint256 public goodwill;
// % share of goodwill (0-100 %)
uint256 affiliateSplit;
// restrict affiliates
mapping(address => bool) public affiliates;
// affiliate => token => amount
mapping(address => mapping(address => uint256)) public affiliateBalance;
// token => amount
mapping(address => uint256) public totalAffiliateBalance;
// swapTarget => approval status
mapping(address => bool) public approvedTargets;
address internal constant ETHAddress =
0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
constructor(uint256 _goodwill, uint256 _affiliateSplit) {
goodwill = _goodwill;
affiliateSplit = _affiliateSplit;
}
// circuit breaker modifiers
modifier stopInEmergency {
if (stopped) {
revert("Temporarily Paused");
} else {
_;
}
}
function _getBalance(address token)
internal
view
returns (uint256 balance)
{
if (token == address(0)) {
balance = address(this).balance;
} else {
balance = IERC20(token).balanceOf(address(this));
}
}
function _approveToken(address token, address spender) internal {
IERC20 _token = IERC20(token);
if (_token.allowance(address(this), spender) > 0) return;
else {
_token.safeApprove(spender, type(uint256).max);
}
}
function _approveToken(
address token,
address spender,
uint256 amount
) internal {
IERC20(token).safeApprove(spender, 0);
IERC20(token).safeApprove(spender, amount);
}
// - to Pause the contract
function toggleContractActive() public onlyOwner {
stopped = !stopped;
}
function set_feeWhitelist(address zapAddress, bool status)
external
onlyOwner
{
feeWhitelist[zapAddress] = status;
}
function set_new_goodwill(uint256 _new_goodwill) public onlyOwner {
require(
_new_goodwill >= 0 && _new_goodwill <= 100,
"GoodWill Value not allowed"
);
goodwill = _new_goodwill;
}
function set_new_affiliateSplit(uint256 _new_affiliateSplit)
external
onlyOwner
{
require(
_new_affiliateSplit <= 100,
"Affiliate Split Value not allowed"
);
affiliateSplit = _new_affiliateSplit;
}
function set_affiliate(address _affiliate, bool _status)
external
onlyOwner
{
affiliates[_affiliate] = _status;
}
///@notice Withdraw goodwill share, retaining affilliate share
function withdrawTokens(address[] calldata tokens) external onlyOwner {
for (uint256 i = 0; i < tokens.length; i++) {
uint256 qty;
if (tokens[i] == ETHAddress) {
qty = address(this).balance - totalAffiliateBalance[tokens[i]];
Address.sendValue(payable(owner()), qty);
} else {
qty =
IERC20(tokens[i]).balanceOf(address(this)) -
totalAffiliateBalance[tokens[i]];
IERC20(tokens[i]).safeTransfer(owner(), qty);
}
}
}
///@notice Withdraw affilliate share, retaining goodwill share
function affilliateWithdraw(address[] calldata tokens) external {
uint256 tokenBal;
for (uint256 i = 0; i < tokens.length; i++) {
tokenBal = affiliateBalance[msg.sender][tokens[i]];
affiliateBalance[msg.sender][tokens[i]] = 0;
totalAffiliateBalance[tokens[i]] =
totalAffiliateBalance[tokens[i]] -
tokenBal;
if (tokens[i] == ETHAddress) {
Address.sendValue(payable(msg.sender), tokenBal);
} else {
IERC20(tokens[i]).safeTransfer(msg.sender, tokenBal);
}
}
}
function setApprovedTargets(
address[] calldata targets,
bool[] calldata isApproved
) external onlyOwner {
require(targets.length == isApproved.length, "Invalid Input length");
for (uint256 i = 0; i < targets.length; i++) {
approvedTargets[targets[i]] = isApproved[i];
}
}
receive() external payable {
require(msg.sender != tx.origin, "Do not send ETH directly");
}
}
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "./ZapBaseV2.sol";
abstract contract ZapOutBaseV3 is ZapBaseV2 {
using SafeERC20 for IERC20;
/**
@dev Transfer tokens from msg.sender to this contract
@param token The ERC20 token to transfer to this contract
@param shouldSellEntireBalance If True transfers entrire allowable amount from another contract
@return Quantity of tokens transferred to this contract
*/
function _pullTokens(
address token,
uint256 amount,
bool shouldSellEntireBalance
) internal returns (uint256) {
if (shouldSellEntireBalance) {
require(
Address.isContract(msg.sender),
"ERR: shouldSellEntireBalance is true for EOA"
);
uint256 allowance =
IERC20(token).allowance(msg.sender, address(this));
IERC20(token).safeTransferFrom(
msg.sender,
address(this),
allowance
);
return allowance;
} else {
IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
return amount;
}
}
function _subtractGoodwill(
address token,
uint256 amount,
address affiliate,
bool enableGoodwill
) internal returns (uint256 totalGoodwillPortion) {
bool whitelisted = feeWhitelist[msg.sender];
if (enableGoodwill && !whitelisted && goodwill > 0) {
totalGoodwillPortion = (amount * goodwill) / 10000;
if (affiliates[affiliate]) {
if (token == address(0)) {
token = ETHAddress;
}
uint256 affiliatePortion =
(totalGoodwillPortion * affiliateSplit) / 100;
affiliateBalance[affiliate][token] += affiliatePortion;
totalAffiliateBalance[token] += affiliatePortion;
}
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(
address indexed previousOwner,
address indexed newOwner
);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(
newOwner != address(0),
"Ownable: new owner is the zero address"
);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount)
external
returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender)
external
view
returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(
address indexed owner,
address indexed spender,
uint256 value
);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(
token,
abi.encodeWithSelector(token.transfer.selector, to, value)
);
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(
token,
abi.encodeWithSelector(token.transferFrom.selector, from, to, value)
);
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(
token,
abi.encodeWithSelector(token.approve.selector, spender, value)
);
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(
token,
abi.encodeWithSelector(
token.approve.selector,
spender,
newAllowance
)
);
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(
oldAllowance >= value,
"SafeERC20: decreased allowance below zero"
);
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(
token,
abi.encodeWithSelector(
token.approve.selector,
spender,
newAllowance
)
);
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata =
address(token).functionCall(
data,
"SafeERC20: low-level call failed"
);
if (returndata.length > 0) {
// Return data is optional
// solhint-disable-next-line max-line-length
require(
abi.decode(returndata, (bool)),
"SafeERC20: ERC20 operation did not succeed"
);
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(
address(this).balance >= amount,
"Address: insufficient balance"
);
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(
success,
"Address: unable to send value, recipient may have reverted"
);
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data)
internal
returns (bytes memory)
{
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return
functionCallWithValue(
target,
data,
value,
"Address: low-level call with value failed"
);
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(
address(this).balance >= value,
"Address: insufficient balance for call"
);
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) =
target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data)
internal
view
returns (bytes memory)
{
return
functionStaticCall(
target,
data,
"Address: low-level static call failed"
);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data)
internal
returns (bytes memory)
{
return
functionDelegateCall(
target,
data,
"Address: low-level delegate call failed"
);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) private pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}